1,4

Table of n, a(n) for n=1..76.

Accumulate[Table[Floor[Sqrt[2]n]-2Floor[n/Sqrt[2]], {n, 120}]] (* Harvey P. Dale, Mar 08 2017 *)

(PARI) first(n)=my(s); vector(n, k, s+=a(n)=sqrtint(2*k^2)%2) \\ Charles R Greathouse IV, Sep 02 2015

Cf. A083035, A083037, A083038.

Sequence in context: A075458 A267861 A253548 * A241920 A202305 A195778

Adjacent sequences: A083033 A083034 A083035 * A083037 A083038 A083039

nonn

Benoit Cloitre, Apr 17 2003

approved